Because it is equal.

So ∠ 1+∠2=69.

That is ∠BOC= 180-69=. . .

(2)90 + 1/2∠A=∠BOC

Because it is equal.

so∠ 1+∠2 = 1/2( 180-∠A)

So ∠1+∠ 2 = 90-1/2 ∠ a.

So180-(∠1+∠ 2) =180-(90-1/2 ∠ a) = 90+1/2 ∠.

The first question is ∠ DFC = 22 because it is a right angle, and ∠ C = 68 because it is the sum of internal angles, which means ∠ B = 68.

F = 90, because it is vertical.

∠ EDB = 22, so∠ EDF = 68 because of the sum of the inner angles.